Spell Caster

How to do it

Hold a dumbbell in each hand with a pronated grip. Your feet should be wide with your hips and knees extended. This will be your starting position.
Begin the movement by pulling both of the dumbbells to one side next to your hip, rotating your torso.
Keeping your arms straight and the dumbbells parallel to the ground, rotate your torso to swing the weights to your opposite side.
Continue alternating, rotating from one side to the other until the set is complete.

What muscles does the Spell Caster work?: Mainly the abs, with help from the glutes, shoulders.
What equipment do I need?: Dumbbell.
Is it good for beginners?: Yes, it is rated beginner level.
How do I track progress on it?: Log each set and beat the weight or reps from last time. Liftrung shows your last set beside the next one and estimates your one-rep max from your sets.

Exercise descriptions: free-exercise-db, public domain.